(4-hydroxy-5-alkylphenyl) alkanoic acid esters of polyols

ABSTRACT

ESTERS DERIVED FROM (4-HYDROXY-5-ALKYLPHENYL)-ALKANOIC ACIDS, OPTIONALLY SUBSTITUTED IN TEH 2- OR 3-POSITION OF THE PHENYL RING BY A SECOND ALKYL GROUP, AND ALKANE POLYOLS ARE STABILIZERS OF ORGANIC MATERIAL NORMALLY SUBJECT TO OXIDATIVE DETERIORATION. THEY ARE PREPARED BY CONVENTIONAL ESTERIFICATRION TECHNIQUES. TYPICAL EMBODIMENTS ARE ETHYLENE GLYCOL BIS(3 - (3,5-DI-BUTYL-4-HYDROXPHENYL) PROPIONATE AND PENTAERY THRITOL TETRAKIS(3-(3,5-DI-BUTYL4-HYDROXPHENYL)PROPIONATE).

United States Patent 3,644,482 (4-HYDROXY-5-ALKYLPHENYL) ALKANOIC ACIDESTERS 0F POLYOLS Martin Dexter, Briarclitf Manor, John D. Spivack,Spring Valley, and David H. Steinberg, Bronx, N.Y., assignors toCiba-Geigy Corporation, Greenburgh, N.Y.

No Drawing. Continuation-impart of application Ser. No. 359,460, Apr.13, 1964, which is a continuation-in-part of application Ser. No.276,192, Apr. 29, 1963, which is a continuation-in-part of applicationSer. No. 164,618, Jan. 5, 1962, which in turn is a continuation-in-partof application Ser. No. 148,738, Oct. 30, 1961. This application Sept.26, 1969; Ser. No. 861,475

Int. Cl. C07c 69/76 US. Cl. 260-473 R 21 Claims ABSTRACT OF THEDISCLOSURE Esters derived from (4-hydroxy-5-alkylphenyl)-alkanoic acids,optionally substituted in the 2- or 3-position of the phenyl ring by asecond alkyl group, and alkane polyols are stabilizers of organicmaterial normally subject to oxidative deterioration. They are preparedby conventional esterification techniques. Typical embodiments areethylene glycol bis[3 (3,S-di-t-butyl-4-hydroxyphenyl) propionate] andpentaerythritol tetrakis[3-,(3,5-di-t-butyl- 4-hydroxyphenyl propionate]CROSS REFERENCE This is a continuation-in-part of copending applicationSer. No. 359,460, filed Apr. 13, 1964, now abandoned. Ser. No. 359,460is a continuation-in-part of Ser. No. 276,192 filed Apr. 29, 1963, nowabandoned, which is a continuation-in-part of Ser. No. 164,618 filed,Jan. 5, 1962, now abandoned, which is a continuation-in-part of Ser. No.148,738, filed Oct. 30, 1961, now abandoned.

DETAILED DESCRIPTION This invention pertains to compounds of theformula:

wherein R is methyl, ethyl or an a-branched alkyl group of from 3 tocarbon atoms;

R is hydrogen, methyl, ethyl or an ut-blill'lCi'lCd alkyl group of from3 to 10 carbon atoms;

x has a value of from 1 to 6;

n has a value of from 2 to 6;

Z is an aliphatic hydrocarbon of the formula:

in which y has a value of from 2 to 18 when n is 2 and a value of from 3to 6 when n is greater than 2, the

value of y in all cases being equal to or greater than that of n.

It will be observed that the compounds of the present invention exhibitone alkyl group (R in a position ortho to the hydroxy group. A secondlike or different alkyl group (R is optionally present either (a) in theother position ortho to the hydroxy group (the 3-position) or (b) metato the hydroxy group and para to the first alkyl group (the 2-position).These alkyl groups will be methyl,

ethyl or when higher than ethyl, an rat-branched alkyl group of from 3to 10 carbon atoms. By the term abranched alkyl group is intended one inwhich the carbon 3,644,482 Patented Feb. 22, 1972 atom of the alkylgroup which is bound to the phenyl group is also bound to at least twoother carbon atoms of the alkyl group.

Thus the monoor dialkylphenolic group includes for example3,S-di-t-butyl-4-hydroxyphenyl, 3,S-dimethyl-4-hydroxyphenyl,3,5-di-isopropyl-4-hydroxyphenyl, 2,S-dimethyl-4-hydroxyphenyl,2-methyl-4-hydroxy-S-t-butylphenyl,2-methyl-4-hydroxy-5-isopropylphenyl,3-methyl-4-hydroxy-5-t-butylphenyl, 3,5-diethyl-4-hydroxyphenyl and thelike. Preferred phenolic groups are those having at least one branchedgroup such as isopropyl, t-butyl or the like in a position ortho to thehydroxy group.

The mono or dialkyl-4-hydrophenyl group is bound to an alkanoyl unit offrom 2 to 7 carbon atoms. The hydrocarbon portion of this alkanoyl unitis represented by (C H2x) and may be of a straight or, when x is greaterthan 1, branched chain. A preferred alkanoyl group is the 3-propionylgroup.

Two or more (as determined by the integer n) of these monoordialkylphenylalkanoyl groups are then bound through a like number ofoxygen atoms to the hydrocarbon residue of a polyol. The polyol fromwhich these esters are derived will thus consist of the straight orbranched chain hydrocarbon residue of the formula C,.H and a number ofhydroxy groups equal to n. When n is two, i.e., the polyol is a diol,this hydrocarbon residue will have from 2 to 18 carbon atoms. When n isgreater than two; i.e., the polyol is a triol, tetrol, pentol or hexol,the hydrocarbon residual will have from 3 to 6 carbon atoms. In allcases the number of hydroxy groups and the resulting number ofalkylphenylalkanoyloxy groups (as designated by n) will be equal to orless than the number of carbon atoms (y) in the hydrocarbon residue;i.e., since each carbon atom of the hydrocarbon residue can bear onlyone hydroxy group, y is equal to or greater than n.

These monoand dialkylhydroxyphenylalkanoic acid esters of alkane polyolsare stabilizers of organic material normally subject to oxidativedeterioration as by light and/or heat. Materials which are thusstabilized include synthetic organic polymeric substances such as vinylresins formed from the polymerization of vinyl halides or from thecopolymerization of vinyl halides with unsaturated polymerizablecompounds, e.g., vinyl esters, a,flunsaturated ketones, u,/3-unsaturatedaldehydes and unsaturated hydrocarbons such as butadienes and styrene;poly-u-olefins such a spolyethylene, polypropylene, polybutylene, andthe like, including copolymers of poly-aolefins; polyisoprene;polychloroprene; polychlorohydrin; terpolymers of ethylene, propyleneand a non-conjugated diene such as 1,4-hexadiene, ethylidenenorbornene,dicyclopentadiene or the like polybutadiene; polyurethanes such as areprepared from polyols and organic polyisocyanates; polyamides such aspolyhexamethylene adipamide; polyesters such as polymethyleneterephthalates; polycarbonates; polyacetals; polystyrene;polyethylenoxide; and copolymers such as those of high impactpolystyrene containing copolymers of butadiene and styrene and thoseformed by the copolymerization of acrylonitrile, butadiene and/ orstyrene. Other materials stabilized according to the present inventioninclude lubricating oil of the aliphatic ester type, e.g.,di-(2-ethylhexyl)azelate, pentaerylthritol tetracaproate and the like;animal and vegetable derived oils, e.g., linseed oil, fat, tallow, lard,peanut oil, cod liver oil, castor oil, palm oil, corn oil, cotton seedoil and the like; hydrocarbon materials such as gasoline, both naturaland synthetic, diesel oil, mineral oil, fuel oil, drying oil, cuttingfluids, waxes, resins and the like, fatty acids such as soaps and thelike.

In general the stabilizers of this invention are employed from about0.005% to about by weight of the stabilized composition, although thiswill vary with the particular substrate. An advantageous range is fromabout 0.05 to about 5%, especially 0.1% to about 1%. These compounds areparticularly useful for the stabilization of polyolefins such aspolypropylene and polyethylene. They can be blended before or afterpolymerization or sprayed on the surface of films, fabrics, filaments orthe like to provide effective stabilization.

These compounds can also be used in combination with other additivessuch as antioxodants, sulfur-containing esters such as DSTDP, DLTDP andthe like, pourpoint depressants, corrosion and rust inhibitors,dispersing agents, demulsifiers, antifoaming agents, carbon black,accelerators and other chemicals used in rubber compounding,plasticizers, color stabilizers, diand trialkyland-alkylphenylphosphites, heat stabilizers, ultraviolet light stabilizers,dyes, pigments, metal chelating agents, dyesites and the like. Oftencombinations such as these, particularly the sulfur containing esters,the phosphites and/or the ultraviolet light stabilizers, will producesuperior results in certain applications to those expected by theproperties of the individual components. In addition, certain of thecompounds of the present invention while demonstrating somewhat lessantioxidant activity than other compounds of this invention, arenevertheless more attractive from the standpoint of economics of preparation. Often the antioxidant properties of such compounds can bedramatically enhanced by the use of a small amount of a compound such asDSTDP or DLTDP.

The compounds of the present invention can be pre pared via conventionalesterification procedures. These include treatment of a polyol of theformula:

(HO}nZ (II) with at least it equivalents of an acid of the formula:

t HO- P -(C;Hzx)-COH R (III) or an acid chloride or lower alkyl esterthereof. Direct esterification witth the acid is conducted in thepresence of an acidic catalyst such as p-toluenesullfonic acid withremoval of the water formed as through distillation.

When an acid chloride of the acid is utilized, the reaction is generallyconducted in the presence of an acid binding agent such as pyridin whichcan also serve as the solvent. Cosolvents such as benzene or chloroformcan also be added to improve solubility.

Use of a lower alkyl ester of an acid of Formula III, such as the methylor ethyl ester, involves treatment of the polyol with up to a excess,preferably from 5 to 10% excess, over the stoichiometric amount of theester. This reaction is catalyzed with a hydride or lower alkoxide of analkali metal, such as lithium hydride, lithium methoxide or sodiummethoxide. These catalysts are employed in an amount from about 0.01 toabout 0.30 molar equivalent per mole of polyol. The reaction isconducted at elevated temperatures and under reduced pressure, the loweralkanol which is formed being removed by distillation.

The products thus obtained by these methods are generally solids orthick liquids and can be purified when desired through conventionaltechniques such as crystallization chromatography, distillation or thelike. For many applications the products need not be extensivelypurified.

The polyols of Formula II are well known and most are commerciallyavailable. Some are available as a mixture of isomers and can be used assuch to yield a mixture of two or more esters of Formula I which neednot be separated.

The acids and alkyl esters of Formula III are generally known and in anyevent can be readily symthesized from alkylated phenols. Acids ofFormula III where x is 1 can be prepared for example throughchloromethylation of an alkylphenol (such as are described as startingmaterials in US. Pat. No. 2,838,571) followed by treatment with sodiumor potassium cyanide and hydrolysis of the resultantalkylhydroxyphenylacetonitrile. The acids and esters of Formula IIIwhere x is two or greater can be readily prepared by the methods of U8.Pat. 3,247,240 through the Friedel-Crafts reaction utilizing alkylphenol and an alkyl ester of chloroformylalkanoic acid followed byreduction of the alkyl substituted 4-hydroxybenzoylalkanoate (or thesaponified free acid) as for example through a Clemmensen reduction orthrough reaction of an alkyl metal phenolate with a halo substitutedalkanoate.

The acid chloride of the acids of Formula III are obtained through theuse of thionyl chloride while the corresponding alkyl esters areobtained through conventional esterification techniques described above.

Typical of the various pathways for the preparation of these startingmaterials are the following procedures:

(A) Methyl 3 (3,5-di-t-butyl-4-hydroxyphenyl)propionate.To 500 parts byvolume of dry t-butyl alcohol in a flask fitted with mechanical stirrer,inert gas inlet, thermometer, condenser and dropping funnel are added2.1 parts of potassium metal. After the ensuing reaction is complete,there are added 37.3 parts of 2,6-di-t-butyl phenol, followed rapidly by17.7 parts of methyl acrylate. The stirred reaction mixture is heated to50 C. for 18 hours and allowed to cool. The solvent is removed underreduced pressure and the residual mass neutralized by addition of dilutehydrochloric acid. This mixture is then extracted with two portions of200 parts by volume each of ethyl ether. The combined ethereal extractsare washed with two portions of parts by volume each of water and thendried over anhydrous sodium sulfate. The ether layer is removed byfiltration and concentrated on a steam bath. The residual oily mass isthen vacuum distilled. The fraction collected at -130 C./0.1 mm.crystallizes upon standing to yield methyl3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, M.P. 63.064.5 C.Recrystallization from hexane yields a white solid, M.P. 66-665 C.

Utilization of 2-methyl-6-t-butylphenol, 2,6-di-isopropylphenol,Z-t-butyl-S-methylphenol and Z-t-butylphenol in the above procedureyields methyl 3-(3-methyl-4-hydroxy-S-t-butylphenyl)propionate, B.P.136l44 C./0.02 mm., methyl3-(3,5-di-isopropyl-4-hydroxyphenyl)propionate, B.P. -132" C./0.4 mm.,methyl 3-(2-methyl- 4-hydroxy-5-t-butylphenyl)propionate, M.P. 75.5-77.5C. and methyl 3 (3-t-butyl-4-hydroxyphenyl)propionate, M.P. 146-147 C.

(B) Ethyl a-(3,5-di-t-butyl-4-hydroxyphenyl)isobutyrate. -To 200 partsby volume of dry t-butyl alcohol in a suitable flask fitted withmechanical stirrer, inert gas inlet, thermometer, condenser and droppingfunnel is added 22.4 parts of potassium t-butoxide, 41.2 parts of2,6-di-t-butylphenol and 50 parts by volume of triethylene glycoldimethyl ether. The dark green solution is stirred and a solution of anequimolar portion of ethyla-bromo-a-methylpropionate in 50 parts oft-butyl alco- 1101 is added dropwise over 20-60 minutes. After addition1s complete, the reaction is refluxed for 1 hour, the solution thenbeing neutral. The reaction mixture is poured into water and extractedwith ether. The ethereal solutron is washed with water and dried and theether removed by distillation, the product being isolated by vacuumdistillation. The corresponding methyl ester, which is alternativelynamed as methyl3-(3,5-di-t-butyl-4-hydroxyphenyl)-2,2-dimethylpropionate, is similarlyobtained from methyl a-bromo-a-methylpropionate.

In a similar fashion, utilizing ethyl u-bromopropionate, there isobtained ethyl 2-(3,5-di-t-butyl-4-hydroxyphenyl) propionate, M.P. 5456C.

7-(3-methyl t-butyl 4 hydroxyphenyl)heptanoic acid-To a cooled (5 C.)solution of 103 parts of ethyl 6-chloroformyl hex-anoate in 100 parts byvolume of ethylene chloride is rapidly added with Stirring 133 parts ofgranular anhydrous aluminum chloride. To this mixture is next added asolution of 88 parts of 2-methyl-6-t-butylphenol in 500 parts by volumeof ethylene chloride. The reaction mixture is stirred at -5 C. for 5hours and then allowed to slowly attain room temperature overnight. Atthe end of this time the material is poured over ice, rendered acidicwith 6 N hydrochloric acid and extracted with ether. The combinedextracts are successively washed with water, dilute aqueous sodiumbicarbonate solution and saturated aqueous sodium chloride solution.After drying over sodium sulfate, the solvent is removed under reducedpressure to yield ethyl 6-(3-methyl-5-t-butyl-4-hydroxybenzoyl)hexanoate, which is saponified with excess potassiumhydroxide in methanol. After acidification of the reaction mixture, thesolid, comprising 6-(3-methyl- 5-t-butyl-4-hydroxybenzoyl)hexanoic acid,is subjected to a Clemmenson reduction as modified by Martin [J.A.C.S.58, 1438 (1936)] to yield 7-(3-methyl 5 t butyl-4-hydroxyphenyl)heptanoic acid which is esterified with ethanol andp-toluenesulfonic acid to yield the corresponding ethyl ester.

In a modification of this Friedel-Crafts reaction, 2,6-dimethylphenol istreated with acrylonitrile in the presence of aluminum chloride to yield3-(3,5-dimethyl-4-hydroxyphenyl)propionitrile. Upon hydrolysis of thisand esterification of the resulting free acid with methanol andptoluenesulfonic acid, there is obtained methyl3-(3,5-dimethyl-4-hydroxyphenyl)propionate, M.P. 70-83 C.

The following examples set forth the manner and process of makingtypical embodiments of the invention without being a limitation thereofand include the best mode contemplated by the inventors for carrying outthe invention.

Example 1.l,2-propylene glycol bis-[3-(3,5-di-t-butyl- 4-hydroxyphenyl)propionate] A mixture consisting of 16.7 parts 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid, 1.90 parts propylene glycol, 2.5 partsp-toluene sulfonic acid monohydrate and 300 parts by volume of tolueneis refluxed until a constant quantity of water has been collected in aDean-Stark water trap.

After cooling, the mixture is diluted with 300 parts by volume ofbenzene and washed successively with the following: water, 0.5 N sodiumhydroxide, water and saturated sodium chloride. After drying over sodiumsulfate, the solvent is removed under reduced pressure to yield1,2-propylene glycol bis-[3-(3,5-di-t-butyl 4 hydroxyphenyl)propionate](13.1 parts). This material is further purified by chromatography overalumina. Elution with hexane produces a minor amount of yellow oilfollowed by the desired product which crystallizes spontaneously anddemonstrates a melting point of 70 C.

Calc. for C H O (percent): C, 74.45; H, 9.45; O, 16.08. Found (percent):C, 74.23; H, 9.72; O, 16.13.

By utilizing equivalent amounts of 1,6-hexane diol in place of propyleneglycol and 3-(3-methyl-4-hydroxy-5-tbutylphenyl)propionic acid in placeof 3-(3,5-di-t-butyl-4- hydroxyphenyl)propionic acid, there is obtained1,6-hexane diol bis-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propionate],M.P. 105-108 C.

Similarly the use of 3-(3,5-dimethyl-4-hydroxyphenyl)- propionic acidwith 1,6-hexanediol yields 1,6-hexanediolbis[3-(3,S-dimethyl-4-hydroxyphenyl)propionate] as a syrup, anal, Ccalc. 71.46, found 71.41; H calc. 8.14, found 8.01.

Utilization of 3,5-di-t-butyl-4-hydroxyphenylacetic acid with ethyleneglycol similarly yields ethylene glycol bis (3,5 di t butyl 4hydroxyphenylacetate), M.P. 112-115 C.

Example 2.-Ethylene glycol bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate] A mixture consisting of 13.9 parts3-(3,5-di-t-butyl-4- hydroxyphenyl)propionic acid, 1.24 parts ethyleneglycol, 1.0 part p-toluene sulfonic acid monohydrate and 300 parts byvolume of benzene is refluxed until a constant amount of water has beenseparated by azeotropic distillation.

After cooling, the solution is diluted with parts by volume of benzeneand successively washed with the following: water, 0.33 N sodiumhydroxide, 0.5 N sodium hydroxide, 5% hydrochloric acid, water andfinally with saturated aqueous sodium chloride solution. After dryingover sodium sulfate, benzene is evaporated to yield 8.7 parts ofethylene glycol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] whichis crystallized from 95% ethanol, M.P. 146-147".

Example 3.Neopentylglycol bis-[3-(3,5-di-t-butyl-4- hydroxyphenyl)propionate] Methyl 3- 3 ,5 -di-t-butyl-4-hydroxyphenyl propionate (21.1parts), 3.12 parts neopentylglycol and 0.378 parts of sodium methoxideare heated under nitrogen at 130 for 1 /2 hours. The methanol thusformed is collected in Dry -Ice acetone cooled trap. After thetheoretical amount of methanol is collected, the reaction mixture isheated at 150/0.05 mm. for 3 hours. At the end of this time, thematerial is dissolved in hexane and filtered. The filtrate is thenconcentrated and recrystallized from 95% ethanol and thoroughly dried toyield neopentylglycol bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], M.P. 8182.

In a similar fashion, the following diols are substituted in equivalentamounts for neopentylglycol.

(a) 2-methyl-l,4-pentanediol (b) 1,8-octanediol (c)2,4-dimethyl-2,4pentanediol (d) 1,9-nonanediol (e) 1,5-pentanediol (f)1,12-dodecanediol (g) 1,18-octadecanediol There are thus respectivelyobtained (a) 2-methyl-l,4-pentanediolbis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], M.P. l-08-ll3 C. andC., mixture of D. L. and racemic forms.

(b) 1,8-octanediol 'bis[3-(3,5-di-t-butyl 4 hydroxyphenyl)-propionate],M.P. 1l71l9 C.

(c) 2,4-dimethyl 2,4 pentanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], M.P. 144-146 C.

(d) 1,9-nonanediol bis[3-(3,5-di-t-butyl 4 hydroxyphenyl)propionate],M.P. 485l C.

(e) l,5-pentanediol bis[3-(3,5-di-t-butyl 4 hydroxyphenyl)propionate],M.P. 88-91 C.

(f) 1,12-dodecanediol bis[3-(3,5-di-t-butyl 4 hydroxyphenyl)propionate],M.P. 6569 C.

(g) 1,18-octadecanediol bis[3-(3,5-di-t-butyl 4 hydroxyphenylpropionate] Example 4.Ethylene glycol bis-(3,5-di-t-butyl-4-hydroxyphenylacetate A mixture consisting of 13.2 parts of3,5-di-t-butyl-4- hydroxyphenylacetic acid, 1.24 parts of ethyleneglycol, 1.7 parts of p-toluene sulfonic acid monohydrate and 330 partsby volume of benzene are treated according to the procedure ofExample 1. The washed and dried benzene solution obtained from thereaction mixture is evaporated to yield 9.3 parts of ethylene glycolbis(3,5- di-t-butyl-4-hydroxyphenylacetate) which is further purified byrecrystallization, M.P. 116-117.

Example 5.l,l2-octadecanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] To a mixture of 7.16 parts of1,12-octadecanediol and 7 90 parts by volume of pyridine at atemperature of from to C. are added over a 1 /2 hour period 16.30 partsof 3-(3,5-di-t-butyl-4-hydroxyphenyD-propionyl chloride. The mixture isthen stirred at room temperature for 16 hours and at 50 C. for one hourand then poured into a mixture of 100 parts by vouume of 6 Nhydrochloric acid and 800 parts of water. This mixture is extracted fivetimes with 200 parts by volume of diethyl ether and the combinedextracts washed three times with dilute hydrochloric acid, five timeswith water and twice with saturated sodium chloride solution. Afterdrying over sodium sulfate, the solution is concentrated under reducedpressure and the residue chromatographed on alumina, eluting withheptane to yield the product.

Analysis.-Ca1cd. (percent): C, 77.37; H, Found (percent): C, 77.27; H,10.85.

In a similar fashion but utilizing 5.4 parts of3-(3,5-dit-butyl-4-hydroxyphenyl)-2,2-dimethylpropionyl chloride and0.381 part of pentaerythritol and reacting these in a solvent mixture ofparts by volume of pyridine and 6 parts by volume of benzene at to C.for 17 hours, there is obtained pentaerythritoltetrakis-[3-(3,5-di-tbutyl-4-hydroxyphenyl -2,2-dimethylpropionate]Analysis.--Calcd. (percent): C, 75.47; H, 9.69. Found (percent): C,74.78; H, 9.37.

By utilizing 0.191 part of pentaerythritol in 25 parts' by volume ofpyridine and 2.27 parts of 3-(3,5-di-t-butyl-4-hydroxyphenyl)-3,3-dimethylpropionyl chloride, the reaction beingconducted by stirring at room temperature for 2.0 hours and at 50 C. for37 hours, there is obtained pentaerythritol tetrakis [3-(3,5-di-t-butyl4 hydroxyphenyl) -3,3-dimethylpropionate], M.P. 166169 C., from heptane.

Analogously prepared from 0.54 parts of pentaerythritol and 6.84 partsof 3-(3,5-di-tbutyl-4-hydroxyphenyl)-2-methylpropionyl chloride, in asolvent mixture of 50 parts by volume of pyridine and 2 parts by volumeof chloroform, is pentaerythritoltetrakis[3-(3,5-di-tbutyl-4hydroxyphenyl)-2-methylpropionate], M.P. 150-154 C.

Example 6.-Pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] Pentaerythritol (6.8 parts) and lithiumhydride (0.0885 part) are added to a reaction vessel equipped with anagitator, Dean-Stark trap and nitrogen inlet. The mixture is heateduntil the contents are molten (about 220 C.) and then cooled below 50 C.Methyl 3-(3,5-di-tbutyl-4 hydroxyphenyl)propionate (64.5 parts) is thenadded and the reaction mixture heated at 185-190 C. for 13 hours withstirring. During this time, nitrogen is continuously introduced toprovide an inert atmosphere and remove the generated methanol. Thereaction mixture is then cooled and 500 parts by volume of benzene arethen aded. The mixture is neutralized with glacial acetic acid andheated until a nearly complete solution is realized. After clarificationand filtration, the reaction mixture is heated under reduced pressure toremove the solvent, cooled, then treated wtih 400 parts by volume ofhexane and filtered. Chromatography over neutral alumina with elutionwith hexane produces an initial yellow impurity followed by the desiredproduct which is freed of solvent by evaporation. The material,alternatively named tetrakis- [rnethylene3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionyloxy]methane, is a clearamber glass which softens at 50 C.

Calc. for C'73H19g012 (percent): C, 74.45; H, 9.24. Found (percent): C,74.62; H, 9.33.

Alternatively this compound is prepared by slurrying 6.8 parts ofpentaerythritol with 50 parts by volume of dimethylsulfoxide and adding0.177 part of lithium hydride, followed by 64.5 parts of methyl3-(3,5-di-t-butyl-4- hydroxyphenyl)propionate. The reaction mixture isheated at -90 C. under 15-20 mm. with stirring until no more methanol isevolved. The solvent is then removed under diminished pressure and thecooled residue taken up in 300 parts by volume of benzene. Glacialacetic acid is added to neutralize the mixture, which is then filteredto remove a small quantity of insoluble material. The filtrate is washedwith water until neutral, then dried over sodium sulfate, filtered andstripped of solvent. The residue is freed of unreacted starting ester bydistillation, 120-l40 C./ 0.1 mm. The residue thus comprises theproduct. Upon recrystallization from isopropanol or n-hexane, the M.P.is l23-125 C.

In a similar fashion the following compounds are obtained from theappropriate polyols and methyl esters:

(a) 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],M.P. 103-106" C.

(b) 1,1,1-trimethylolethane tris[3-(3,5-di-tbuty1-4-hydroxyphenyl)propionate], M.P. 106108 C.

(c) 1,3-propanediol bis[3-3,5-di-t-butyl-4-hydroxyphenyl)propionate],M.P. 71-73 C.

(d) pentaerythritol tetrakis [3-(3-isopropyl-4hydroxy- 5 -t-butylphenylpropionate] (e) pentaerythritol tetrakis {3-[3,5-di-(2-octyl)-4-hydroxyphenyl] propionate} (f) pentaerythritol tetrakis[3-(3-ethyl-4-hydroxy-5-tamylphenyl) propionate] (g) pentaerythritoltetrakis [7-(3-methyl-4hydroxy-5- t-butylphenyl)heptanoate] (h)1,4-butanediol bis[3-(3-,5-di-t-butyl-4-hydroxyphenyl)propionate], M.P.8284 C.

(i) 1,1,1-trimethylolethane bis[3,5-di-t-butyl-4-hydroxyphenylacetate],M.P. 102104 C.

(j) ethylene glycol bis[3-(3-t-butyl-4-hydroxyphenyl) propionate]Example 7.--1,1,1-trimethylolpropanetri-[3-(3,5-di-tbutyl-4-hydroxyphenyl) propionate] To a reaction vesselas described in Example 6 are added 585 parts of methyl3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 67.1 parts of1,1,1-trimethylolpropane and 1.33 parts of lithium hydride. Thereactants are heated at 125-150 C. for 1 /2 hours at atmosphericpressure under nitrogen and then for an additional 4 hours at 110- C. at0.2 to 0.5 mm. One thousand parts by volume of hexane are then addedafter cooling and the mixture then warmed with stirring and filtered.The filtrate is treated with 15 parts by volume of glacial acetic acidwith stirring, followed by an excess of sodium carbonate with stirring.After refiltering, the filtrate is freed of solvent and volatileimpurities by slowly heating to 152/ 0.22 mm. The glassy residueconstitutes the product, which is alternatively named as n-propyl1,1,1-tris[methylene-3- (3,5-di-t-bntyl-4 hydroxyphenyl)propionate] andsoftens between 5570 C.

Calc. for C57H86O9 (percent): C, 74.80; H, 9.47. Found (percent): C,74.45; H, 9.25.

Similarly prepared are:

(a) glycerine tris[3,5 di t butyl 4 hydroxyphenyl) propionate], a glass(calc. (percent): C, 74.27; H, 9.23; found (percent): C, 74.16; H,9.15).

(b) 1,1,1 trimethylolbutane tris]3 (3,5-di-t-butyl 4-hydroxyphenyl)propionate], a glass (calc. (percent): C, 74.96; H, 9.24;found (percent): C, 75.06; H, 9.67).

(c) pentaerythritol tetrakis[3-(3,5-diisopropyl-4-hydroxyphenylpropionate], a glass calc. (percent):C, 73.28; H, 8.70; found (percent): C, 73.41; H, 8.74).

(d) glycerine tris(3,5 di t butyl 4 hydroxyphenylacetate), a glass(calc. (percent): C, 73.69; H, 8.97; found (percent): C, 73.62; H,8.73).

(e) pentaerythritol tetrakis[3(3,5-di-t-octyl-4-hydroxyphenyl)propionate.

(f) pentaerythritol tetrakis( 3,5 di t butyl-4-hydroxyphenylacetate), asyrup (calc. percent): C, 73.89; H, 8.98; found (percent): C, 74.01; H,8.70).

Example 8.--Sorbitolhexakis[3-(3,5-di-t-butyl-4-hydroxyphenylpropionate] By employing 9.1parts of sorbitol, 0.239 part of lithium hydride and 96.6 parts ofmethyl 3 (3,5-di-t-butyl-4- hydroxyphenyl)propionate in 50 parts byvolume of dimethyl sulfoxide in the alternative procedure of Example 6,there is obtained sorbitol hexakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], which softens at 75 C. and melts at 90 C.

(Calc. (percent): C, 74.36; H, 9.12; found (percent): 0, 74.66; H,9.20).

Example 9.-l,2,3-butanetriol tris-[3-(3,5-dit-butyl- 4-hydroxyphenylpropionate] The compound of this example is obtained according to thealternative procedure of Example 6 employing 10.6 parts of1,2,3-butanetriol, 0.239 part of lithium hydride and 97.1 parts ofmethyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate in 50 parts byvolume of dimethyl sulfoxide.

Example l0.Pentaerythritol tetrakis[3-(2-methyl-4- hydroxy-S-t-butylphenyl) propionate] An equivalent amount of methyl3-(2-methyl-4-hydroxy- S-t-butylphenyl)propionate is substituted formethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl)propionate in the procedure ofExample 6 to yield the above product as a hard colorless glass,softening at 80 C.

Analysis.-Calc. (percent): C, 72.58; H, 8.38. Found (percent): C. 72.45;H, 8.31.

Example 11 wherein R is methyl, ethyl or an tat-branched alkyl group offrom 3 to carbon atoms,

R is hydrogen, methyl, ethyl or an a-branched alkyl group of from 3 to10 carbon atoms;

x has a value of from 1 to 6;

n has a value of from 2 to 6 Z is an aliphatic hydrocarbon of theformula:

in which y has a value of from 2 to 18 when n is 2 and a value of from 3to 6 when n is greater than 2, the value of y in all cases being equalto or greater than that of n.

2. A compound according to claim 1 wherein n is 2 and Z is a divalentaliphatic hydrocarbon of the formula in which y has a value of from 2 to18.

3. A compound according to claim 2 characterized by the formula:

I R g 10 wherein each of R and R is methyl, ethyl or an abranched alkylgroup of from 3 to 6 carbon atoms.

4. A compound according to claim 3 wherein each of R and R is tertiarybutyl.

5. A compound according to claim 4 which is a 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid diester of a diol selectedfrom the group consisting of ethylene glycol; propylene glycol;1,3-propanediol; 1,4-butanediol; 1,5-pentanediol; neopentyl glycol;1,6-hexanediol; 2-methyl-l,4- pentanediol;2,2,4-trimethyl-1,3-pentanediol; 2,4-dirnethyl-2,4-pentanediol; 2,4,4trimethyl-1,6-hexanediol; 1,8- octanediol; 1,9-nonananediol;1,10-decanediol; 1,2-dodec anediol; 1,12-octadecanediol and1,18-octadecanediol.

6. The diester according to claim 5 which is ethylene glycol bis [3- 3,5di-t-butyl-4-hydroxyphenyl -propionate] 7. The diester according toclaim 5 which is 1,2-propylene glycolbis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propiomate].

8. The diester according to claim 5 which is neopentylglycol bis- 3, 3,5 -di-t-butyl-4-hydroxyphenyl propionate] 9. The diester according toclaim 5 which is 1,6-hexanediol bis- 3,5-di-t-butyl-4-hydroxyphenylpropionate] 10. The diester according to claim 5 which is 1,9-nonanediolbis-[3 (3,S-di-t-butyl-4-hydroxyphenyl)propionate].

11. A compound according to claim 1 wherein n has a value of from 3 to 6and Z is an aliphatic hydrocarbon of the formula:

in which y has a value of from 3 to 6, the value of y being equal to orgreater than the value of n.

12. A compound according to claim 11 characterized wherein each of R andR is methyl, ethyl or an a-branched alkyl group of from 3 to 6 carbonatoms.

13. A compound according to claim 11 wherein each of R and R is tertiarybutyl.

14. A compound according to claim 13 which is pentaerythritoltetrakis-[3-(3,5-di-t-butyl 4 hydroxyphenyl) propionate].

15. A compound according to claim 13 which is 1,1,1- trimethylolethanetris[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate] 16. A compoundaccording to claim 13 which is 1,1,1- trimethylolpropanetris[3-(3,5-di-t butyl-4-hydroxyphenyl) propionate] 17. A compoundaccording to claim 13 which is 1,1,1- trimethylolpropanetris[3-(3,5di-t=butyl-4-hydroxyphenyl) propionate] 18. A compoundaccording to claim 13 which is glycerine tris[3-(3,S-di-t-butyl-4-hydroxyphenyl) propionate] 19. A compound accordingto claim 13 which is sorbitol hexakis [3- 3,5-di-t-butyl-4-hydroxyphenyl) propionate] 20. A compound according toclaim 12 which is pentaerythritol tetrakis[3-(3-methyl-4-hydroxy-5-t-butylphenyl pro pionate] 21. A compoundaccording to claim 12 which is pentaerythritol tetrakis[3-(3,5-dimethyl-4-hydroxyphenyl)propionate].

References Cited UNITED STATES PATENTS 3,112,338 11/1963 Sm-ntny et al.260473 R 3,285,855 11/1966 Dexter et a1 260473 R X LORRAINE A.WEINBERGER, Primary Examiner J. F. TERAPANE, Assistant Examiner US. Cl.X.R.

